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INSTRUCTIONS   IN 
MILITARY  SIGNALING 


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INSTRUCTIONS  IN 

MILITARY   SIGNALING 


FOR   THE  USE  OF  THE 

REGULAR  AND  VOLUNTEER  ARMY 

AND   THE  ORGANIZED  MILITIA 

OF  THE  UNITED  STATES 


BY 

Captain  HOWARD   A.   GIDDINGS 

BRIGADE  SIGNAL  OFFICER,   CONNECTICUT  NATIONAL  GUARD 
AUTHOR    OF    MANUAL    FOR    CYCLISTS,    ETC. 


SECOND    EDITION 


h 


NEW    YORK 

D.    APPLETON    AND    COMPANY 

1899 


Copyright,  1896, 

bt  d.  appleton  and  COMPANT. 


State  of  Connecticut, 
Adjutant-General's  Office, 

Hartford,  November  12,  1896. 
General  Orders,  No.  19. 

(Extract.) 
The  manual  of  Instructions  in  Military  Signaling,  pre- 
pared by  Major  Howard  A.  Giddings,  Brigade  Signal  Officer, 
Connecticut  National  Guard,  is  hereby  adopted  for  use  of 
the  Connecticut  National  Guard. 

By  order  of  the  Commander-in-Chief. 

Charles  P.  Graham, 

Adjutant-  General, 
Official  : 

William  E.  F.  Landers, 

Assistant  Adjutant- General, 


M277809 


PREFACE. 


this  book  has  been  induced  by 
ensed  and  practical  Manual  of 
ipted  to    present  requirements 

aiental  principles  of  signaling 
'ed,  changes  in  the  code,  im- 
is  and  methods,  and  the  ad  op- 
means  of  transporting  signal- 
ive  rendered  much  of  existing 
obsolete. 

gnals  and  Gallup's  Handbook 
lave  both  been  consulted,  and 
ely  followed ;  but  it  is  believed 
nmch  that  is  new,  and  which 
t  time  in  print. 

rein  for  the  use  of  the  helio- 

'eviated  from  those  of  Captain 

il  Corps,  U.  S.  Army,  author- 

.  A.  1888,  with  such  changes  as 

the  Myer  system  of  signaling  necessitates. 

The  instructions  in  military  photography  are  large- 
ly taken  from  the  Manual  of  Photography,  by  First 
Lieutenant  Samuel  Reber,  Signal  Corps,  IJ.  S.  Army. 
The  chapter  on  the  use  of  the  bicycle  and  transporta- 
tion of  apparatus  is  based  on  the  results  of  five  years^ 
5 


Signal  Flags. 

M.  R.  S. — Signaling 'by 
fiag-s,  as  the  term  is  now 
universally  understood, 
c\-as  invented  in  the  year 
1854  by  Surgeon  Myer  of 
the  United  States  army. 
Before  Surgeon  IVEyer's 
invention  the  only  flag 
signaling  was  by  color, 
but  realizing  the  Inade- 
quacy of  such  a  mode  of 
conveying  information, 
Dr.  Myer  studied  out  the 
system  of  "wigwagging" 
or  talking  by  making 
motions  with  the  flag,  a 
sort  of  deaf  and  dumb 
telegraphy,  which  has 
since  been  adopted  by 
pretty  nearly  all  the  na- 
tions of  the  world. 
M«     *     * 

i/.eu    uy     vji .   \J.   iJiJ^  Xl.  l^ 


6  PREFACE. 

experience  with  the  bicycle  in  the  Signal  Corps  of  the 
National  Gruard  of  Connecticut — the  first  State  to  es- 
tablish and  develop  a  signal  corps,  and  by  whose  troops 
the  bicycle  was  first  used  in  the  military  service  in  the 
United  States. 

Instructions  in  electrical  signaling  have  been  pur- 
posely omitted.  No  standard  field  equipment  for  either 
telephoning  or  telegraphing  has  yet  been  adopted  for 
the  army,  and  it  is  useless  to  attempt  to  lay  down  in- 
structions for  the  use  of  experimental  or  temporary 
apparatus.  Such  instructions  for  the  operating  of  per- 
manent telegraph  lines  as  could  be  included  in  a  work 
of  this  size  would  be  of  little  value  to  the  average  sig- 
nalman, and  still  less  to  the  professional  operator, 
upon  whom  we  must  always  rely  for  the  operation  of 
such  lines. 

It  is  intended  to  include  herein  such  practical  in- 
structions in  military  signaling  as  will  best  insure  the 
successful  practice  of  the  art  by  the  Organized  Militia. 

Howard  A.  Giddings, 
Major,  Brigade  Signal  Officer, 
Connecticut  National  Guard. 

Hartford  Connecticut,  October  1,  1896. 


CONTENTS. 


PAGE 

The  Myer  System  of  Army  and  Navy  Signaling  : 

Alphabet      .        .  , -9 

Numerals 9 

Abbreviations 9 

Conventional  Signals 10 

Code  Calls .10 

Instructions  for  using  the  System       .         .        .        .10 
To  signal  with  Flag,  Torch,  Hand  Lantern,  or  Beam 

of  Search  Light 11 

Flash  Signals,  with  Heliograph,  Search  Light,  or 

Lantern 14 

Sound  Signals,   with  Fog   Whistle,  Fog  Horn,  or 

Bngle 15 

The  Flag .        .16 

Signaling  with  the  Flag 16 

The  Torch 18 

Signaling  with  the  Torch 18 

The  Heliograph 21 

Field  Equipment 21 

Setting  up  and  adjusting 25 

Remarks 27 

Field  Stations  .        .        . 31 

Messages  in  Cipher 38 

The  Compass 41 

Maps 42 

Military  Photography 43 

7 


8  CONTENTS. 

PAGE 

Transportation  of  Apparatus 45 

Organization,  Equipxment,  and  Command  ,  .  .49 
Appendix  i: 

The  Morse  Telegraph  Code .  .  .  .  "^.  .51 
Appendix  ii: 

Use  of  Myer  Code  for  Telegraphing  ,  .  .  .53 
Appendix  hi: 

Table  of  Magnetic  Declinations  in  the  United  States.  55 
Index 63 


THE  MYER  SYSTEM  OF 
AEMY  AND  NAVY  SIGNALING. 


ALPHABET. 

1. 

A.... 

....22 

J.... 

. . . 1122 

S 

.  212 

B.... 

.2112 

K... 

...2121 

T 

....2 

C... 

...121 

L.... 

....221 

U 

..112 

D.... 

...222 

M    .. 

...1221 

V 

.1222 

E.... 

....12 

N... 

11 

W 

.1121 

F.... 

..2221 

0... 

21 

X 

.2122 

G.... 

..2211 

P... 

...1212 

Y 

..111 

H.... 

...122 

Q  •  •  • 

...1211 

Z 

.2222 

I 

1 

R... 

....211 

tion 

.1112 

NUMERALS. 

1 

...1111 

6 

.2211 

2 

...2222 

7 

..1222 

3 

...1112 

8 

..2111 

4 

...2221 

9 

..1221 

5 

. . . 1122 

0 

..2112 

ABBREVIATIONS. 

A- 

-After 

H- 

-Have 

T— The 

W 

—Word 

B- 

-Before 

N- 

-Not 

U— You 

Wi-With 

C- 

-Can 

R- 

-Are 

Ur— Your        Y- 

-Yes. 

9 

10  INSTRUCTIONS  IN 

CONVENTIONAL   SIGNALS. 

2.  End  of  a  word  :  3 

End  of  a  sentence  (or  address)  :  33 

End  of  a  message  :  333 

Acknowledgment,  or  ''  I  understand  "  :  22  22  3 

Error:  12  12  3 

Signature  follows  :  sig.  3 

Repeat  after  (word) :  121  121  3  22  3  (word) 

Repeat  last  word :  121  121  33 

Repeat  last  message :  121  121  121  333 

Wait  a  moment :  1111  3 

Move  a  little  to  right :  211  211  3 

Move  a  little  to  left :  221  221  3 

Numerals  follow  (or)  numerals  ended :  XX  3 

Signal  faster :  2212  3 

Cease  signaling :  22  22  22  333 

CODE   CALLS. 

3.  I  C  U — International  Code  Use. 

T  D  U—  (Navy)  Telegraph  Dictionary  Use. 

G  L  U — (Navy)  Geographical  List  Use. 

G  S  U— (Navy)  General  Signal  Use. 

C  A  U— Cipher  "A'^  Use.* 

C  B  U— Cipher  "  B  "  Use.* 

C  C  U— Cipher  ''  C  "  Use.* 

N  L  U— Navy  List  Use. 

V  N  U — Vessel's  Numbers  Use. 

INSTRUCTIONS  FOR  USING  THE   SYSTEM. 

4.  The  whole  number  opposite  each  letter  or  nu- 
meral stands  for  that  letter  or  numeral. 

*  For  preconcerted  use  in  or  with  the  Navy. 


MILITARY   SIGNALING. 


11 


At  the  end  of  each  word,  abbreviation,  or  conven- 
tional signal,  "  3  "  is  made. 

Make  a  slight  pause  after  each  letter  and  also  after 
"front." 

Each  station  should  have  its  own  signal  or  call  let- 
ter, as  Washington,  "  W"  ;  and  each  signalist  his  per- 
sonal signal,  as  Jones,  "  Jo." 

If  the  call  letter  of  the  station  wanted  be  not 
known,  signal  "  A  "  until  acknowledged. 

If  the  sender  discovers  that  he  has  made  an  error, 
he  should  make  the  "front"  and  12  12  3  after  which 
he  proceeds  with  the  message,  beginning  with  the  word 
in  which  the  error  occurred. 

Numbers  which  occur  in 
the  body  of  a  message  must 
be  spelled  out  in  full. 

Numerals  may  be  used  in 
signaling  between  stations  hav- 
ing naval  signal  books,  using 
the  code  calls. 

TO  SIGNAL  WITH  FLAG,  TORCH, 
HAND  LANTERN,  OR  BEAM  OF 
SEARCH   LIGHT. 


posi- 


5.  There  are  but  one 
tion  and  three  motions. 

The  first  position  is  with  the 
flag  or  other  appliance  held  ver- 
tically, the  signalman  facing 
squarely  toward  the  station  witli 
which  it  is  desired  to  communi- 
cate. 

The  first  motion,  or  "one" 


First  position. 


12 


INSTRUCTIONS  IN 


or  "  1 "  :  the  signal  is  waved  to  the  right  of  the  sender, 
and  will  embrace  an  are  of  90°,  starting  with  the  ver- 
tical and  returning  to  it,  and  will  be  made  in  a  plane 


T 


exactly  at  right  angles  to  the  line  connecting  the  two 
stations. 

.  The  second  motion,  or  "two"  or  "2,"  is  a  similar 
motion  to  the  left  of  the  sender. 

To  make  the  third  motion,  "front"  or  "three''  or 
"3,"  the  signal  is  waved  to  the  ground  directly  in  front 


MILITARY  SIGNALING. 


^^^^u 


r:-"--> 


of  the  sender,  and  instantly  re- 
turned to  the  first  position. 

To  use  the  torch  or  hand  lan- 
tern, a  foot  light  must  be  used  as 
a  point  of  reference  to  the  mo- 
tion.    The  lantern  is  more  con-         ^^     ^ 
veniently  swung  out  upward  by  3 

hand  from  the  foot  light  for  "  1 " 
and  "  2  "  and  raised  and  lowered  vertically  for  "  3  ". 

6.  To  call  a  station. — Signal  its  initial  or  call  let- 
ter until  acknowledged. 


14  INSTRUCTIONS  IN 

To  acknowledge  a  call. — Signal  "  I  understand,"  fol- 
lowed by  the  call  letter  of  the  acknowledging  station. 

To  break  or  stop  the  signals  from  the  sending 
station. — Hold  the  flag  or  other  appliance  in  the  "  first 
position  "  until  sender  stops  sending. 

To  start  the  sending  station  after  breaking. — Sig- 
nal 121  121  3  22  3  followed  by  the  last  word  correctly 
received.  The  sender  will  immediately  resume  his 
message,  beginning  with  the  word  indicated  by  the 
receiver.  If  nothing  has  been  received,  signal  121 121 
121  333. 

To  acknowledge  receipt  of  a  message. — Signal  22 
22  3  followed  by  the  personal  signal  of  the  receiver. 

FLASH   SIGNALS, 
WITH   HELIOGRAPH,    SEARCH   LIGHT,   OR  LANTERN. 

7.  Use  short  flash  for  "  1,"  two  short  flashes  in 
quick  succession  for  "  2,"  and  a  long  steady  flash  for 
"  3."  The  elements  of  a  letter  should  be  slightly  longer 
than  in  sound  signals. 

To  call  a  station. — Signal  its  initial  or  call  letter 
until  acknowledged,  then  turn  on  a  steady  flash  until 
answered  by  a  steady  flash.  Both  stations  will  then 
adjust,  each  on  the  other's  flash.  When  adjustments 
are  satisfactory,  the  station  called  will  cut  off  its  flash, 
and  the  calling  station  will  proceed  with  the  message. 

To  acknowledge  a  call. — Signal  "  I  understand." 

To  break  or  stop  the  signals  from  the  sending 
station. — Make  a  rapid  succession  of  short  flashes  with- 
out pause  until  sender  stops  sending. 

To  start  the  sending  station  after  breaking. — 
(Same  as  with  flag.) 

Adjustment. — If  sending  station  gets  out  of  adjust- 


MILITARY  SIGNALING.  lo 

ment,  receiving*  station  calls  for  adjustment  by  turn- 
ing on  steady  flash.  Sender  will  answer  by  steady 
flash  and  will  adjust  on  receiver's  flash.  When  ad- 
justment is  satisfactory  to  receiving  station,  it  will 
cut  off  its  flash  and  sender  will  proceed,  commencing 
with  the  last  word  sent. 

To  acknoivledge  receipt  of  a  message. — (Same  as 
with  flag.) 

SOUND    SIGNALS, 
WITH   FOG  WHISTLE,   FOG  HORN,   OR  BUGLE. 

8.  Use  one  toot  (about  half  a  second)^  for  "  1,"  two 
toots  in  quick  succession  for  ''2,"  and  a  blast  (about 
two  seconds  long)  for  ''  3."  The  ear  and  not  the  watch 
is  to  be  relied  upon  for  the  intervals. 

The  signal  of  execution  for  all  tactical  or  drill 
signals  will  be  one  long  blast  followed  by  two  toots  in 
quick  succession. 

In  the  use  of  any  other  appliance,  such  as  a  bell,  by 
which  a  blast  can  not  be  given,  three  strokes  in  quick 
succession  will  be  given  in  place  of  the  blast  to  indi- 
cate ''  3." 

When  more  than  two  vessels  are  in  company,  each 
vessel,  after  making  "  I  understand,"  should  make  her 
call  letter,  that  it  may  be  certain  which  vessel  has  ac- 
knowledged. 

ORDER  OF   SENDING   A   MESSAGE. 

.     9.  1 — Number  of  message. 
2 — Place  from,  and  date. 
3— Address  in  full  (followed  by  33). 
4 — Body  of  message. 
5 — Sig  3  (signature  follows). 
6 — Signature. 


16  INSTRUCTIONS  IN 

Note. — In  pronouncing  the  whole  numbers  of  the  Myer  alpha- 
bet, A  is  called  "twenty-two";  B,  "twenty-one  twelve";  C,  "one 
twenty-one  "  ;  D,  "  two  twenty-two  "  ;  E,  "  twelve  "  ;  F,  "  twenty- 
two  twenty-one  "  ;  G,  "twenty-two  eleven  "  ;  H,  "one  twenty-two," 
etc.  This  method  is  more  convenient  and  expeditious  than  any 
other. 

THE  FLAG. 

10.  Signal  flags  are  made  of  muslin  or  other  mate- 
rial of  light  and  close  texture,  are  square  in  shape,  and 
have  a  smaller  square  in  the  center,  comprising  one 
ninjth  of  the  surface  of  the  flag,  of  a  diff'erent  color 
from  the  body  of  the  flag. 

Those  commonly  used  are  :  The  white  flag,  four 
feet  square,  having  a  red  block  sixteen  inches  square 
in  its  center.  The  red  flag,  four  feet  square,  having 
a  white  block  sixteen  inches  square  in  its  center.  The 
white  flag,  two  feet  square,  hav^ing  a  red  block  eight 
inches  square  in  its  center.  The  red  flag,  two  feet 
square,  having  a  white  block  eight  inches  square  in 
its  center. 

In  addition  to  the  above,  six-foot  flags  with  centers 
two  feet  square  are  often  used,  and  black  flags  with 
white  centers  are  sometimes  the  most  suitable,  as  in 
case  of  sky  backgrounds. 

All  flags  are  fitted  with  tapes  on  one  edge,  one  foot 
apart,  for  tying  them  to  the  staif.  The  staif  is  in  two, 
three,  or  four  joints,  each  four  feet  in  length.  Two  or 
three  joints  are  ordinarily  used,  but  the  longer  the 
distance  the  larger  the  flag  and  longer  the  staff. 

SIGNALING   WITH   THE   FLAG. 

11.  The  signalman  is  first  instructed  in  the  use  of 
the  two-foot  flag,  on  the  upper  joint.     He  takes  the 


MILITARY  SIGNALING.  ,  17 

position  of  the  soldier,  faces  exactly  toward  the  re- 
ceiving" station,  with  the  staff  vertical  in  front  of  the 
center  of  his  body,  holding  it  with  either  hand  at  the 
butt,  which  should  be  at  the  height  of  the  waist. 

An  imaginary  line,  fram  a  point  between  the  feet 
of  the  sender  to  the  receiver,  is  called  the  line  of 
vision. 

In  swinging  the  flag,  each  motion  to  the  right  or 
left  should  be  exactly  at  right  angles  to  the  line  of 
vision,  and  each  front  motion  should  be  in  the  line  of 
vision.  To  insure  this,  stakes  may  be  driven  in  the 
line  of  vision  a  short  distance  in  front  of  the  flagman 
and  at  right  angles  to  it,  the  same  distance  to  the  right 
and  left.  The  staft'  should  point  in  the  direction  of 
one  of  these  stakes  at  each  wave. 

Expert  signalmen  will  not  need  the  stakes  for  day 
signaling,  but  they  are  indispensable  for  torch  signal- 
ing at  night. 

The  instructor  should  explain  to  the  recruit  how  to 
keep  the  flag  open  and  prevent  its  fouling  with  the 
staff,  by  giving  the  end  of  the  staft'  a  slight  scoop  as  it 
reaches  the  lowest  point  in  its  motion. 

The  scoop  should  be  made  against  the  wind. 

The  importance  of  clean,  clear  cut  motions  of  the 
flag  in  a  plane  exactly  at  right  angles  to  the  line  of 
vision  can  not  be  overestimated. 

The  staff  should  be  kept  as  upright  as  possible,  and 
the  flag  kept  open,  as  when  fouled  on  the  staft'  it  may 
become  quite  invisible  during  several  motions. 

In  a  clear  atmosphere  the  four-foot  flag  may  be 
read  with  the  naked  eye  four  or  five  miles ;  with  a 
field  glass  or  telescope  about  twice  as  far. 

2 


18  INSTRUCTIONS  IN 


THE  TORCH. 


12.  The  Graham-Meyer  army  sio^nal-torch  consists 
of  an  asbestos  flying-torch,  an  asbestos  foot-torch,  fly- 
ing-torch can,  foot-torch  can,  spike  for  foot  torch, 
clamp  for  attaching  flying  torch  to  staff,  and  funnel — 
all  packed  in  a  cylindrical  sole-leather  case  carried 
by  a  shoulder  strap. 

The  illuminant  used  is  kerosene  oil,  which  is  car- 
ried in  copper  canteens  holding  one  gallon  each,  two 
of  which  accompany  each  torch. 

The  oil  canteen  should  have  a  nozzle,  and  an  orifice 
for  filling,  through  which  air  may  be  admitted  behind 
the  oil,  while  emptying,  to  facilitate  its  flow. 

The  flying- torch  clamp  is  made  to  fit  the  second 
joint  of  the  standard  three-jointed  staff.  The  clamp 
and  spike  are  carried  in  a  special  pocket  on  the  outside 
of  the  case. 

When  packed,  the  torches  are  inverted  inside  their 
respective  cans,  the  cup  which  catches  the  drippings 
of  the  torch  forming  a  cover. 

SIGNALING  WITH   THE   TORCH. 

13.  Unpack  the  kit  and  half  fill  each  of  the  torch 
cans  with  kerosene  oil.  Immerse  the  torches  for  a 
few  minutes. 

Screw  the  spike  to  the  foot  torch  and  plant  it  firmly 
in  the  ground  in  the  line  of  vision,  about  twelve  feet 
directly  in  front  of  the  point  where  the  sender  is  to 
stand. 

When  it  is  impossible  to  use  the  spike  the  foot 
torch  may  be  set  on  top  of  its  can,  but  this  is  to  be 
avoided,  as  the  can  soon  gets  hot. 


MILITARY  SIGNALING. 


19 


20 


INSTRUCTIONS  IN 


Attach  the  clamp  to  the  staff  and  screw  the  flying 
torch  to  the  clamp.  Place  the  cans  in  a  convenient 
position  near  the  signalmen. 

Light  the  foot  torch  with  a  match,  and  when  ready 
to  signal,  light  the  flying  torch  from  the  foot  torch. 


Torches  packed. 

At  the  conclusion  of  each  message  the  flying  torch 
is  extinguished. 

To  extinguish  the  torch,  plunge  it  in  the  kerosene, 
tightly  closing  the  can  as  quickly  as  possible.  The 
torch  thus  becomes  saturated  anew  during  the  inter- 
vals in  signaling. 

Upon  removing  it  from  the  can,  allow  it  to  drain 
for  a  moment. 

Should  either  torch  need  resaturating  during  the 


MILITARY   SIGNALING.  21 

sending  of  a  message,  at  the  end  of  a  word,  signal 
"  Wait  a  moment,"  and  resaturate. 

When  the  foot  torch  needs  resaturating,  the  flying 
torch  should  be  held  near  the  ground  in  its  place. 
A  foot  light  must  always  be  kept  burning  while  the 
station  is  in  operation. 

Care  should  be  taken  not  to  tip  over  or  spill  oil  on 
the  outside  of  the  cans  or  on  the  ground,  as  it  gets  on 
fire  and  makes  the  cans  hot  and  difficult  to  handle. 

The  torches  are  light  and  safe,  and  if  every  part 
but  the  flying  torch  be  lost  or  broken,  signaling  may 
be  effected  so  long  as  some  kerosene,  a  pole,  and  a 
piece  of  wire  for  attaching  the  torch,  can  be  obtained. 

An  improvised  foot  torch  may  be  made  by  soaking 
a  small  pile  of  leaves  or  grass  with  kerosene,  or  even 
by  pouring  the  kerosene  on  the  ground. 

An  additional  supply  of  kerosene  may  be  carried 
in  a  metal  can,  the  same  shape  as  a  bicycle  luggage 
case,  and  attached  to  a  wheel  in  a  similar  manner. 

The  matches  carried  should  be  wind  or  Vesuvius 
matches — i.  e.,  those  so  prepared  as  to  be  inextinguish- 
able by  wind  or  rain. 

THE   HELIOGRAPH. 

14.  The  field  heliograph  equipment  consists  of — • 
X.  A  sole-leather  pouch,  containing  : 

One  sun  mirror.        ^  t     i       j  •  i      i 

One  station  mirror.  \  Inclosed  m  a  wooden  box. 

One  screen.  One  sighting  rod.  One  screw-driver. 
Y.  A  smaller  pouch,  sliding  by  two  loops  upon  the 

strap  of  the  larger,  containing  one  mirror  bar. 
z.  A  skeleton  case,  of  leather,  containing  two  tripod 

stands. 


22 


INSTRUCTIONS  IN 


c.  Sun  mirror. 

D.  Station  mirror. 

E.  Mirror  supports. 

F.  Tangent  screws  for  revolving  mirror  about 

horizontal  axis. 

G.  Mirror  bar. 

H.  Tangent  screw  with  ball  bearings  for  revolv- 
ing mirror  about  vertical  axis. 

I.  Clamp  screw  for  attaching  mirror  bar  to 
tripod. 

K.  Spring  for  clamping  mirrors  and  sighting 
rod. 

L.  Sighting  rod  with  movable  disk. 

M.  Screen. 

N.  Key  for  screen. 


MILITARY  SIGNALING. 


23 


24  INSTRUCTIONS   IN 

15.  The  sun  mirror  has  an  unsilvered  spot  at  its 
center,  the  station  mirror  a  paper  disk.  In  other  re- 
spects they  are  similar.  The  tangent  screw  attach- 
ment to  the  frame  affords  the  means  of  revolving  the 
mirror  about  a  horizontal  axis. 

The  support  to  the  frame  has  a  conical  projection 
accurately  turned  to  fit  the  socket  of  the  mirror  bar 
and  grooved  to  receive  the  clamp  spring. 

The  screen  has  two  shutters,  operated  by  means  of 
a  key. 

The  base  of  the  frame  carries  a  female  screw  for  at- 
tachment to  the  tripod. 

16.  The  sighting  rod  is  fitted  to  the  socket  of  the 
mirror  bar,  and  is  clamped  in  the  same  manner  as  the 
mirrors.  It  carries  at  one  end  a  movable  disk,  which 
when  turned  down  reveals  the  front  sight.  A  piece 
of  white  paper  should  be  slipped  into  the  disk  to  re- 
ceive the  ''shadow  spot,"  and  a  slight  puncture  made 
therein,  coincident  with  the  point  of  the  front 
sight,  as  guide  in  adjustment.  Vertical  adjustment 
of  the  disk  is  made  possible  by  loosening  the  milled 
slide. 

17.  The  mirror  bar  is  provided  with  a  clamp 
threaded  to  fit  the  screw  of  the  tripod.  The  release  of 
the  clamp  permits  movement  of  the  bar  independent 
of  the  screw.  At  one  end  is  attached  the  tangent 
screw  for  revolving  mirror  about  a  vertical  axis,  and 
it  should  be  remembered  that  under  all  circumstances 
the  sun  mirror  is  to  he  clamped  to  this  end,  while  the 
socket  at  the  other  extremity  is  designed  to  receive 
the  station  mirror  or  the  sighting  rod.  A  movable 
spring  is  placed  under  each  end  of  the  bar  for  clamp- 
ing mirrors  and  sighting  rod. 

18.  The  tripods  are  similar,  the  screw  of  either 


MILITARY   SIGNALING.  25 

serving  equally  well  for  the  attachment  of  mirror  bar 
or  screen. 

Both  are  provided  with  a  hook  for  the  suspension 
of  a  weight,  to  give  greater  stability  when  required. 

SETTING   UP  AND   ADJUSTING. 

19.  The  position  of  the  sun  is  the  guide  for  deter- 
mining whether  one  or  two  mirrors  should  be  used. 
When  the  sun  is  in  front  of  the  operator — that  is,  in 
front  of  a  plane  through  his  position,  at  right  angles 
to  the  line  of  vision — the  sun  mirror  only  is  required. 
With  the  sun  in  rear  of  this  plane  both  mirrors  should 
be  used,  although  a  single  mirror  may  often  be  worked 
to  advantage  with  the  sun  well  back  of  the  operator. 
In  the  former  case  the  rays  of  the  sun  are  reflected 
from  the  sun  mirror  direct  to  the  distant  station.  In 
the  latter  they  are  reflected  from  the  sun  mirror  to  the 
station  mirror,  thence  to  the  distant  station. 

20.  With  one  mirror :  Set  the  tripod  firmly  on  flie 
ground,  attach  the  bar  to  the  tripod,  insert  and  clamp 
in  their  appropriate  sockets  the  sun  mirror  and  the 
sighting  rod.  the  latter  with  its  disk  turned  down. 
Sight  through  the  center  of  the  mirror  and  turn  the 
bar  and  raise  or  lower  the  sighting  rod  until  the  cen- 
ter of  the  mirror,  point  of  sighting  rod,  and  distant 
station  are  accurately  in  line  ;  then  clamp  the  bar  firm- 
ly to  the  tripod,  being  careful  not  to  disarrange  the 
alignment. 

Turn  up  the  disk  of  the  sighting  rod.  Move  the 
mirror  by  means  of  the  slow-motion  screws  until  the 
"shadow  spot"  falls  upon  the  disk  of  the  sighting 
rod.     The  flash  will  then  be  visible  to  the  distant  ob- 


26  INSTRUCTIONS  IN 

The  shadow  spot  must  he  kept  in  the  center  of 
the  disk  while  signaling,  and  should  he  kept  there 
hy  constant  adjustment  of  the  mirror.  Attach  the 
screen  to  the  tripod,  and  place  it  close  to  and  in  front 
of  the  sig-hting-  disk  so  as  to  intercept  the  flash. 

21.  With  two  mirrors :  Set  the  tripod  firmly  on 
the  g-round,  clamp  the  bar,  diagonally  across  the  line 
of  vision  to  the  distant  station,  clamp  the  sun  mirror 
facing"  the  sun  to  the  end  of  bar  with  tangent-screw 
attachment,  and  the  station  mirror  facing  the  distant 
station  to  the  other  socket. 

Stooping  down,  the  head  in  rear  of  and  near  the 
station  mirror,  turn  the  sun  mirror  by  means  of  its 
slow-motion  screws  until  the  whole  of  the  station  mir- 
ror is  seen  reflected  in  the  sun  mirror,  and  the  unsil- 
vered  spot  and  reflection  of  the  paper  disk  accurately 
cover  each  other.  Still  looking  into  the  sun  mirror, 
turn  the  station  mirror  until  the  reflection  of  the  dis- 
tant station  is  brought  accurately  into  line  with,  or  is 
cohered  by,  the  unsilvered  spot  and  the  reflection  of 
the  paper  disk.  After  this  the  station  mirror  must  not 
be  touched. 

Now,  stepping  behind  the  sun  mirror,  throw  upon 
the  station  mirror  a  full  flash  from  the  sun  mirror,  so 
that  the  shadow  spot  falls  upon  the  center  of  the  paper 
disk.  The  flash  will  then  be  visible  at  the  distant 
station. 

The  shadow  spot  must  he  kept  in  the  center  of 
the  disk  while  signaling,  and  should  he  kept  there 
hy  constant  adjustment  of  the  mirror.  Attach  the 
screen  to  its  tripod  and  place  it  so  as  to  intercept  the 
flash  from  the  station  mirror. 

22.  Signaling  is  effected  by  depressing  the  screen 
for  periods  of  time  required  to  display  flashes. 


MILITARY   SIGNALING.  27 

"  1 "  is  represented  by  a  momentary  exposition  of 
the  flash. 

"  2  "  by  two  short  flashes  in  quick  succession. 

'  3  "  by  a  lon^  steady  flash. 

It  is  of  the  utmost  importance  that  uniformity  in 
mechanical  movement  of  the  screen  be  cultivated,  as 
lack  of  rhythm  in  the  signals  of  the  sender  entails  un- 
necessary and  vexatious  concentration  of  attention 
upon  the  receiver. 

The  flashes  should  be  sharp  and  clear  cut.  For  a 
"  3  "  dwell  somewhat  upon  the  exposure,  with  a  tend- 
ency to  lengthen  rather  than  shorten  the  period  of 
duration. 


Heliograph  station,  roof  of  warehouse. 


REMARKS. 


23.  In  setting  up  the  instrument,  spread  the  tripod 
legs  sufficiently  to  give  a  good  base,  and  on  yielding 
soil  press  firmly  into  the  ground,  the  head  approxi- 


28  INSTRUCTIONS  IN 

mately  level.  In  a  hig-h  wind,  ballast  by  hanging  a 
substantial  weight  to  the  hook. 

If  the  legs  become  loose  at  the  head  joints,  apply 
the  screw-driver  to  the  assembling  screws. 

24.  See  that  the  screen  completely  obscures  (cuts 
off)  the  flash,  also  that  the  flash  passes  entire  when 
the  key  is  depressed. 

The  spiral  spring  should  return  the  screen  sharply 
to  its  normal  position  when  the  key  is  released.  If  it 
fails  to  respond  promptly,  strengthen  or  replace. 

26.  Extra  care  bestotved  on  preliminary  adjust- 
ment is  repaid  by  increased  brilliancy  of  flash. 
With  alignment  absolutely  assured,  and  the  shadow 
spot  at  the  center  of  the  disk,  the  axis  of  the  cone  of 
reflected  rays  is  coincident  with  the  line  of  sight,  and 
the  distant  station  receives  the  greatest  possible  inten- 
sity of  light. 

The  distant  operator  is  necessarily  the  best  judge 
as  to  the  flash  received ;  if,  therefore,  adjustment  is 
called  when  the  shadow  spot  is  at  the  center  of  the 
disk,  alignment  is  at  fault. 

Accuracy  of  alignment  may  be  tested  by  looking 
into  the  sun  mirror,  bringing  the  eye  into  line  with 
the  unsilvered  spot,  the  reflection  of  the  disk,  and  re- 
flection of  the  distant  station.  If  it  is  found  that  a 
line  through  the  center  of  the  unsilvered  spot  and  re- 
flection of  the  disk  strikes  a  little  to  one  side  of  the 
reflection  of  the  distant  station,  grasp  the  mirror  bar 
firmly,  without  loosening  the  clamp,  and  slightly  turn 
it,  so  that  the  reflection  of  the  distant  station  will  be 
brought  accurately  into  line.  If  the  reflection  of  the 
distant  station  appears  slightly  above  or  below  a  line 
through  the  center  of  the  unsilvered  spot  and  reflection 
of  the  disk,  bring  it  into  line  by  pressing  the  front  or 


MILITARY  SIGNALING.  29 

rear  tripod  leg's  farther  into  the  ground,  as  the  case 
may  require. 

26.  The  tendency  of  the  shadow  spot  to  move  off  the 
disk,  due  to  the  apparent  motion  of  the  sun,  is  com- 
pensated for,  without  interrupting  signals,  by  means 
of  the  tangent  screws  of  the  sun  mirror.  The  move- 
ment imparted  to  the  mirror  by  these  screws  does  not 
disturb  alignment,  as  its  center  (the  unsilvered  spot) 
is  at  the  intersection  of  the  axes  of  revolution. 

27.  The  manipulation  of  the  instrument  involves 
but  slight  manual  labor ;  the  strain  on  the  eyes,  how- 
ever, from  the  flash  of  the  mirror  in  receiving,  is 
often  considerable,  but  may  be  modified  by  the  use  of 
stained  glasses. 

Ability  to  read  signals  from  the  heliograph  may  be 
readily  acquired,  but  may  also  be  as  readily  lost  if 
practice  be  discontinued  before  proficiency  is  attained. 
It  should  therefore  be  the  endeavor  to  acquire  such 
facility,  not  only  in  sending  but  in  receiving,  that 
habit  will  come  to  the  aid  even  after  the  lapse  of  con- 
siderable time. 

28.  Minor  parts  of  the  instrument  should  be  dis- 
mounted only  to  effect  repair.  All  steel  should  be 
preserved  from  rust,  and  tangent  screws  and  bearings 
from  dust  and  grit.  The  mirrors  should  invariably  be 
wiped  clean  before  using. 

In  case  of  accident  to  the  sun  mirror  the  station 
mirror  may  be  made  available  as  such  by  removing 
the  paper  disk. 

29.  The  projection  of  the  rays  of  the  sun  upon  a 
screen,  by  reflection  from  plane  mirrors,  demonstrates 
that  for  short  distances  (varying  with  the  size  of  the 
mirrors  employed)  the  figures  of  illumination  are  sim- 
ilar to  those  of  the  mirrors  used.     Removino:  the  mir- 


30  INSTRUCTIONS  IN 

rors  to  a  greater  distance  from  the  screen,  it  is  found 
that  the  shapes  of  the  mirrors  are  no  longer  reflected, 
but  that  all  images  are  circular  and  of  the  same  di- 
ameter. 

Removing  the  mirrors  to  a  still  greater  distance,  it 
is  found  that  the  various  images  are  circular  as  before 
and  of  the  same  diameter,  but  that  this  latter  diameter 
is  greater  than  the  one  previously  obtained.  Repeat- 
ing the  experiment  at  increased  distances,  these  results 
are  confirmed,  with  the  following  conclusions : 

a.  That  up  to  a  certain  distance  the  form  of  the 
mirror  is  reflected  upon  the  screen. 

h.  That  this  distance  once  exceeded,  the  reflected 
images  obtained  from  mirrors  of  various  shapes  and 
sizes  are  all  circular  and  of  equal  diameters  at  equal 
distances. 

c.  That  the  greater  the  distance  from  the  mirror  to 
the  screen,  the  greater  the  diameter  of  the  reflected 
image. 

d.  That  the  images  vary  in  brightness,  the  larger 
mirrors  producing  the  brighter  images. 

It  is  therefore  evident  that  the  advantage  derived 
from  the  use  of  a  large  mirror  consists,  not  in  any  in- 
crease in  the  size  of  the  flash,  but  in  an  increase  of 
brightness — that  is,  capability  of  overcoming  such  ob- 
structions as  fog,  smoke,  haze,  and  consequently  dis- 
tance. 

30.  The  light  from  the  sun  is  projected  upon  the 
surface  of  the  mirror  in  a  cone  of  rays,  and  is  reflected 
in  a  cone  of  the  same  dimensions.  The  angle  within 
which  the  reflection  is  visible  is  that  subtended  by  the 
diameter  of  the  sun.  The  limit  of  the  lateral  extension 
of  the  flash  at  any  given  distance  may  therefore  be 
definitely  determined. 


MILITARY   SIGNALING.  31 

It  is  found  that  the  circle  of  illumination  has  a 
diameter  which  increases  sixteen  and  one  third  yards 
for  every  mile  of  distance  from  the  mirror. 

As  the  diameter  of  the  flash  increases  directly  with 
the  distance  between  stations,  adjustment  of  the  in- 
strument is  quite  as  simple  and  certain  for  great  as  for 
short  distances.  Although  the  margin  of  flash  is  ample, 
so  that  signals  may  be  directed  upon  a  station,  how- 
ever distant,  with  certainty,  yet  it  is  so  slight  relative 
to  the  distance  between  communicating  points  that 
signals  are  invisible  to  one  far  out  of  the  direct  line, 
and  are  therefore  not  liable  to  be  read  by  those  for 
whom  not  intended. 

31.  The  range  over  which  signaling  may  be  effected 
under  favorable  atmospheric  conditions  is  limited  only 
by  the  convexity  of  the  earth.  The  square  mirror  is 
adopted  in  preference  to  the  round,  as  containing  about 
one  fourth  more  reflecting  surface  for  practically  the 
same  packing  space. 

Signaling  at  night,  in  the  squad  room,  may  be  ef- 
fected by  the  employment  of  artificial  light. 

FIELD  STATIONS. 

32.  Each  station  should  have  its  own  signal  or  call 
letter.  A  terminal  station  should  be  manned  by  a 
non-commissioned  olRcer  and  three  men,  and  an  in- 
termediate station  by  an  officer  and  six  men.  A  cen- 
tral station  requires  three  men  to  each  station  with 
which  it  is  in  communication. 

CoTitinuous  work  requires  a  sufficient  number  of 
men  to  form  three  reliefs.  Each  relief  should  consist 
of  the  number  of  men  stated  above.  The  tour  for  each 
relief  should  be  four  hours. 


32  INSTRUCTIONS  IN 

33.  When  signaling  with  the  flag-,  one  man  calls, 
off  the  letters  (not  the  numerals  that  stand  for  them), 
another  sends,  while  the   third   watches   the  distant 
station. 

In  receiving,  one  of  the  men  reads,  one  records,  and 
the  other  is  stationed  at  the  sending  point,  with  flag  at 
*'  front "  or  ''  3,"  to  break  if  necessary. 

When  signaling  with  a  torch,  one  man  calls  off, 
another  sends,  and  the  third  watches  the  distant  sta- 
tion, keeps  torch  cans  filled,  etc.  In  receiving,  one 
man  reads,  another  records,  and  the  third  stands  at 
the  sending  point,  ready  to  break  if  necessary,  keeps 
foot  torch  saturated  and  burning,  etc. 

When  signaling  with  a  heliograph,  one  man  calls 
off,  one  sends,  and  the  third  keeps  adjustment.  The 
man  sending  keeps  watch  of  the  distant  station.  In 
receiving,  one  man  reads,  another  records,  and  the 
third  keeps  adjustment.  The  man  who  reads  stands 
at  screen  to  break  if  necessary. 

If  the  recorder  sees  that  a  word  is  not  intelligible 
or  if  the  readers  are  in  doubt  about  a  letter,  the  sender 
immediately  breaks  the  sending  station  and  signals 
121  121  3  ^"^  3,  followed  by  the  last  word  correctly  re- 
ceived. 

34.  The  officer  or  non-commissioned  officer  in 
charge  of  the  station  is  responsible  for  everything  in 
connection  with  it.  He  gives  his  entire  attention  to 
the  working  of  the  station,  and  will  compel  each 
member  of  the  party  to  attend  strictly  to  his  own 
business.  He  contiimally  notes  the  correctness  of  the 
adjustment  of  the  heliograph,  and  tests  its  alignment 
from  time  to  time.  He  has  charge  of  the  apparatus 
and  equipments,  and  sees  that  all  messages  are  cor- 
rectly copied  and  transmitted,  either  to  the  communi- 


MILITARY  SIGNALING.  33 

eating  station  or  to  the  person  for  whom  they  are  in- 
tended. 

The  person  in  charge  of  a  station  may  never  take 
it  upon  himself  to  make  any  alterations  in  a  message. 
He  must  bear  in  mind  the  confidential  nature  of  the 
work,  and  will  see  that  unauthorized  persons  do  not 
loiter  about  the  station,  and  that  no  one  interferes 
with  the  work  of  the  party.  No  talking  can  be  al- 
lowed while  actual  work  is  going  on,  beyond  the  neces- 
sary calling  off,  and  giving  of  orders. 

An  exact,  copy  of  every  message  sent  and  received 
must  always  be  kept,  with  date  and  hour  of  receipt 
and  transmission. 

Communications  transmitted  by  signals  are  always 
confidential,  and  will  only  be  revealed  to  those  of- 
ficially entitled  to  receive  them. 

35.  A  strict  watch  upon  all  other  stations,  and  upon 
points  from  which  calls  are  likely  to  come,  must  be 
kept  at  all  times. 

Failure  to  promptly  recognize  and  reply  to  calls,  or 
to  correctly  receive  and  transmit  messages,  is  punish- 
able, .in  case  of  either  officers  or  enlisted  men,  as  neg- 
lect of  duty. 

In  case  the  sending  station  can  not  get  an  answer- 
ing signal,  but  has  reason  to  believe  that  its  own  sig- 
nals are  visible,  it  should  send  the  message  repeatedly. 

It  must  be  remembered  that  it  is  the  duty  of  the 
signal  corps  to  transmit  messages,  and  any  excuse  for 
a  failure  to  do  so  may  well  be  received  with  ill  grace. 
Faithful,  persistent,  and,  it  may  be,  desperate  efforts, 
must  be  made  to  fulfill  requirements,  though  in  the 
face  of  unlooked-for  and  adverse  circumstances. 

36.  It  should  be  remembered  that  accuracy  is  of 
paramount    importance,    and    rapidity    in    signaling 


34  INSTRUCTIONS  IN 

must  always  be  subordinated  to  it.  If  any  doubt  as  to 
a  character  exists,  the  sender  will  be  required  to  re- 
peat it. 

37.  In  field  work  it  is  imperative  that  the  greatest 
care  be  taken  in  selecting  the  station. 

Stations  ought  not,  when  it  can  be  avoided,  to  be 
located  exactly  on  an  east  and  west  line,  or  in  the 
line  of  the  apparent  course  of  the  sun.  It  is  impos- 
sible to  signal  in  the  line  of  the  rising  or  setting  sun, 
not  only  on  account  of  the  blinding  light,  but  because 
of  the  haze  in  which  the  landscape  in  the  direction  of 
the  sun  is  very  liable  to  seem  to  be  enveloped. 

A  station  should  not,  if  avoidable,  be  located  in  a 
camp,  or  where  the  white  canvas  of  tents  is  liable  to 
form  the  background.  The  manoeuvering  of  troops  in 
nn  encampment,  the  passage  of  individuals,  the  smoke 
from  the  kitchens,  the  difficulty  of  distinguishing  at 
night  the  signal  torches  or  lights  from  the  changing 
lights  of  the  encam])ment,  and  the  curiosity  of  persons 
not  attached  to  the  station,  make  a  camp  the  most  un- 
suitable locality  for  a  signal  station. 

The  point  chosen  should  be  near  the  headquarters 
of  the  commanding  general,  but  outside  of  the  camp 
and  on  one  side  of  it.  If  no  natural  height  presents,  a 
platform  may  be  built  in  the  top  of  a  tree,  or  a  scaffold 
erected  from  the  ground.  The  tops  of  ordinary  build- 
ings are  to  be  avoided  for  signal  stations,  as  in  night 
signaling,  burning  oil  from  the  torches  is  almost  sure 
to  set  the  building  on  fire. 

38.  Stations  should  invariably  be  on  the  most  ele- 
vated ground  accessible,  and  should  never,  if  avoid- 
able, be  placed  on  low  land.  The  undulation  of  the 
atmosphere  noticeable  on  a  hot  summer  day  is  always 
less  at  a  distance  from  the  earth's  surface,  while  in  the 


MILITARY   SIGNALING.  35 

cool  night  air  the  smoke  and  dust  of  the  day  and  the 
heavy  moving  mists  lie  close  to  the  ground,  obscuring 
the  lowlands. 


Flag  station,  parapet  of  high  building. 

Stations  on  the  tops  of  city  buildings  should,  when 
possible,  be  so  located  as  not  to  be  visible  from  the 
street. 

39.  Signal  officers  should  always  be  supplied  with 
the  best  obtainable  maps  of  the  district  in  which  they 
may  be  working. 

The  maps  should  have  altitudes  indicated  in  figures. 
In  selecting  stations  from  a  map  and  calculating  the 
height  of  intervening  elevations,  due  allowance  should 
be  made  for  the  curvature  of  the  earth. 

The  top  of  a  lighthouse  one  hundred  and  fifty  feet 
above  sea  level  becomes  invisible  from  the.  level  of 
the  water  at  a  distance  of  about  twenty-five  miles. 

The  approximate  increase  in  height  of  intervening 
elevations  between  two  stations  over  the  figures  on 


36  INSTRUCTIONS   IN 

the  map,  resulting"  from  the  curvatm^e  of  the  earth, 
may  thus  be  roug-hly  calculated. 

Officers  should  enter  in  field  books  provided  for 
the  purpose,  sketches  and  minute  descriptions  of  the 
location  of  stations  upon  which  they  have  worked, 
showing  upon  the  sketch,  lines  leading*  to  other  sta- 
tions with  which  communication  may  be  held,  with 
magnetic  courses  to  the  same,  and  any  notes  or  in- 
formation which  might  aid  in  quickly  locating  the 
station  at  some  future  time. 

40.  In  signaling  with  the  flag,  the  background  is 
of  vital  importance. 

It  should  be  of  one  color,  and  the  flagman  should 
be  so  placed  that  all  the  motions  will  be  outlined, 
against  it  when  viewed  from  the  connnunicating  sta- 
tion. Dark  colored  backgrounds,  such  as  green  fields 
or  woods,  are  the  most  satisfactory.  Sky  backgrounds 
are  excellent,  but  are  difficult  to  obtain. 

The  background  may  be  a  long  distance,  sometimes 
many  miles,  behind  the  station.  To  determine  what 
the  background  will  be,  move  along  the  line  of  vision 
in  front  of  your  station,  the  head  accurately  in  line 
with  the  distant  station,  and  observe  your  background 
from  that  position. 

The  flag  used  must  be  of  the  color  which  contrasts 
most  greatly  with  the  color  of  the  background.  In 
the  case  of  landscape  backgrounds  the  white  flag 
should  be  used.  With  sky  backgrounds  use  black 
flags.  With  mixed  backgrounds  red  flags.  In  nine 
cases  out  of  ten  the  white  flag  w411  be  found  best. 

41.  It  is  important  that  every  motion  and  position 
of  the  flag  be  visible  at  the  receiving  station.  It  is 
possible  that  trees  or  bushes  may  hide  the  flag  in  one 
of  its  motions,  although  they  be  a  long  way  off. 


MILITARY  SIGNALING.  37 

To  determine  that  the  flag-man  is  so  placed  that 
nothing"  obstructs  a  view  of  the  flag  in  any  of  its 
motions,  when  viewed  from  the  receiving  station,  go 
to  the  points  to  the  right,  left,  and  front  of  the  flag- 
man, and,  stooping  down,  with  the  face  at  about  the 
height  of  the  flag  at  its  lowest  point,  see  if  the  farther 
station  be  visible  from  there.  If  so,  then  rise,  and  see 
if  the  farther  station  is  visible  as  you  rise. 

The  above  precaution  should  ahvays  be  taken. 

42.  When  using  the  torch,  similar  care  should  be 
taken  that  the  background  does  not  interfere  with  the 
visibility  of  the  light.  No  lights  or  fires  should  be  in 
the  rear  of,  or  near,  the  station.  At  a  distance  of  five 
miles,  a  light  twenty-five  feet  to  one  side  of  the  line  of 
vision  will  interfere  with  the  visibility  of  the  torch. 

For  night  signaling,  stakes  should  be  driven  and 
the  apparatus  prepared  before  dark.  The  torches  will 
work  much  better  if  saturated  for  some  hours  before 
using.  When  the  front  motion  is  made  with  the  fly- 
ing torch  its  flame  should  appear  to  blend  with  the 
foot  torch.  The  signalman  should  stand  exactly  be- 
hind the  foot  torch  and  the  length  of  the  torch  staff 
from  it. 

43.  The  same  precautions,  that  the  torch  be  visible 
throughout  every  motion,  should  be  taken  as  for  the 
flag,  being  even  more  important  in  night  than  in  day 
signaling.  Particular  care  should  be  taken  that  the 
foot  torch  is  not  hidden  by  grass  or  brush.  To  insure 
this,  lie  on  the  ground,  the  face  at  the  level  of  the  foot 
torch,  and  see  if  the  farther  station  can  be  seen.  Also, 
with  the  head  close  to  the  ground,  look  between  the 
signalman's  heels  at  the  distant  station,  and  see  that 
the  foot  torch  is  exactly  in  the  line  of  vision. 

In  case  of  a  high  wind  blowing  from  the  distant 


38  INSTRUCTIONS   IN 

station,  build  a  screen  about  two  feet  high  between 
the  foot  torch  and  the  sender.  The  back  draught  will 
prevent  the  light  being  blown  out.  A  screen  in  the 
same  position  will  also  shield  the  light  should  the  wind 
blow  toward  the  distant  station. 

Screens  may  also  be  built  to  screen  the  foot  torch 
from  a  side  wind,  care  being  taken  not  to  obscure  the 
flying  torch  in  any  position. 

44.  When  signaling  with  the  heliograph,  it  will 
often  be  necessary,  in  opening  communication,  to  find 
the  direction  by  compass.  After  the  course  has  been 
found  the  instrument  should  be  sighted  as  nearly  as 
possible  on  the  point  where  the  distant  station  is  sup- 
posed to  be,  and  the  flash  swept  by  the  slow  motion 
screws  slowly  back  and  forth  in  a  small  arc,  occasion- 
ally changing  it  to  a  little  higher  or  lower  plane. 

Attention  may  often  be  attracted  by  taking  a  spare 
mirror  and  flashing  it  tow^ard  the  distant  station.  The 
flash  may  be  directed  by  selecting  some  near  object 
nearly  in  line  with  the  distant  station,  as  a  reference 
point. 

MESSAGES  I^  CIPHER. 

45.  In  active  service  all  messages  should  be  trans- 
mitted in  cipher.  The  United  States  Army  cipher 
disk  consists  of  two  disks  fastened  concentrically  to- 
gether in  such  a  way  that  they  may  be  revolved,  and 
clamped  at  any  point  by  a  thumbscrew. 

Around  the  edge  of  the  larger  disk  the  alphabet  is 
written  from  left  to  right ;  on  the  smaller  one,  from 
right  to  left. 

If  there  be  no  previous  agreement,  "A''  on  the 
inner  circle  will  be  set  opposite  "  A "  of  the  outer 
circle. 


i  ,  Tt(9« 


n 


kY  SIGNALING. 


39 


The  letters  of  the  message,  which  is  written  in  plain 
English,  are  found  on  the  one  circle,  and  the  letters 
opposite  them  on  the  other  circle  signaled. 


The  operator  at  the  receiving  station  writes  tlie 
message  down  as  it  is  sent,  and  afterward  translates  it 
by  using  his  own  disk,  which  should  be  adjusted  the 
same  as  that  of  the  sender. 

46.  It  is  usual  to  agree  on  a  cipher  word  in  ad- 
vance. The  message  is  divided  into  groups  of  four 
letters  each.  The  first  group  is  enciphered  by  setting 
the  arrow  on  the  inner  disk  at  the  first  letter  of  the 
cipher  word  on  the  outer  circle.  The  second  group  is 
enciphered  by  setting  the  arrow  at  the  second  letter  of 
the  cipher  word,  and  so  on.     When  all  the  letters  of 


40  INSTRUCTIONS  IN 

the  cipher  word  have  been  used  in  turn,  commence  at 
the  first  letter  again. 

In  signaling,  a  front  or  space  signal  is  made  after 
each  group. 

In  enciphering  or  deciphering  a  message,  it  makes 
no  difference  which  disk  the  letters  are  found  on.  The 
result  is  the  same  whether  one  finds  a  letter  on  the  outer 
circle  and  records  the  letter  opposite  it  on  the  inner 
circle,  or  finds  the  letter  on  the  inner  circle  and  records 
the  letter  opposite  it  on  the  outer  circle.  The  circles 
may  be  used  indifi^erently. 

47.  Messages  sent  in  cipher  should,  to  prevent 
errors,  be  repeated  back  by  the  receiving  station.  This 
should  be  done  group  by  group — i.  e.,  as  soon  as  a  group 
of  four  letters  is  received,  it  should  be  repeated  back 
before  the  next  group  is  sent. 

Cipher  dispatches  to  which  the  key  is  unknown 
may  often  be  deciphered  by  the  rule  of  frequency  of 
occurrence  of  letters. 

The  order  of  precedence  among  the  letters,  accord- 
ing to  the  frequency  of  their  occurrence,  is  as  follows  : 
e,  a,  o,  i,  t,  d,  h,  n,  r,  s,  u,  y,  c,  f,  g,  1,  m,  w,  b,  k, 
p,  j,  q,  X,  z.        ^{    — 

The  most  frequent  compounds  are :  th,  ng,  ee,  11, 
mm,  tt,  dd,  and  nn.  . 

48.  Important  dispatches  by  courier  should  not 
only  be  written  in  cipher,  but  may  be  written  in  in- 
visible ink  made  as  follows  : 

Chloride  of  cobalt 50  grains  ; 

Distilled  water 1  lluid  ounce  ; 

Glycerin 10  minims. 

Dissolve  the  chloride  of  cobalt  in  the  distilled  water 
and  add  the  glycerin. 


MILITARY   SIGNALING.  41 

Writing  executed  with  this  ink  is  invisible  on  paper, 
but,  on  warming,  tlie  writing  turns  blue.  On  exposure 
to  damp  air  it  becomes  invisible  again. 

THE   COMPASS. 

49.  In  long-range  signaling  wnth  the  heliograph 
it  will  often  be  necessary  to  use  the  compass,  espe- 
cially when  the  line  and  stations  are  selected  by  the 
map.  In  finding  the  course  from  one  station  to  an- 
other, by  the  map.  it  must  be  remembered  that  the 
meridian  lines  run  toward  the  true  north,  while  the 
compass  needle  points  to  the  magnetic  north. 

The  variation  of  the  compass  for  the  locality  in 
question  must  be  known.  See  Appendix  III  for  table 
of  Magnetic  Declinations  in  the  United  States. 

In  finding  a  magnetic  course  on  the  map  with  a 
l^rotractor,  allowance  must  be  made  for  the  variation 
of  the  needle.  If  the  protractor  readiuj^  between  two 
stations  be  on  that  side  of  north  to  which  the  needle 
varies,  the  amount  of  the  variation  must  be  subtracted 
from  the  protractor  reading  to  get  the  magnetic  course. 
If  the  protractor  reading  of  the  course  between  the 
stations  be  on  the  opposite  side  of  north  from  that  to 
which  the  needle  varies,  then  the  variation  must  be 
added  to  the  reading  to  get  the  magnetic  course. 

60.  The  best  compass  for  signal  work  is  that  called 
a  "military  compass,"  mounted  in  a  square  wooden 
box,  about  three  inches  on  a  side.  It  is  graduated  to 
degrees,  and  reads  from  zero  around  to  360°,  zero  being 
at  the  north  point. 

The  north  and  south  line  is  at  right  angles  to  the 
side  to  which  the  cover  is  hinged,  and  the  cover  has  a 
sighting  line  cut  in  its  under  side,  so  that  when  open 


42  INSTRUCTIONS  IN 

the  line  is  in  prolongation  of  the  north  and  south  line 
of  the  dial. 

In  this  compass  the  west  is  on  the  right-hand  side 
of  north,  and  east  on  the  left  hand,  so  that  when  the 
needle  points  to  the  given  bearing  the  sight  line  will 
point  in  the  desired  direction.  This  saves  calculation 
and  confusion ;  but  when  taking  a  bearing  with  the 
compass  it  must  be  borne  in  mind  that  the  east  and 
west  are  reversed. 

MAPS. 

51.  The  signal  corps  should  always  be  supplied 
with  the  best  obtainable  maps  of  the  country  in  which 
they  may  be  operating.  United  States  topographical 
maps,  in  sections,  are  preferable. 

The  margin  should  be  trimmed  off  the  top  and 
left-hand  sides,  and  each  section  should  be  folded  once 
lengthwise  and  once  crosswise,  making  the  folded  sec- 
tion about  eight  by  ten  inches. 

The  sections  should  be  numbered  both  inside  and 
out  to  correspond  with  the  index,  and  packed  in  a  sole- 
leather  case  carried  by  a  shoulder  strap.  The  map 
should  always  be  carried  in  the  field.  If  such  maps 
are  not  obtainable,  those  supplied  should  have  the  alti- 
tude of  dominant  points,  in  feet,  above  sea  level,  indi- 
cated. 

52.  To  find  the  magnetic  course  between  two  points 
on  the  map,  in  order  that  the  direction  of  one  from 
the  other  may  be  found  by  the  compass,  draw  a  light 
pencil  line  by  means  of  a  straight  edge  between  the 
points.  Take  a  transparent  protractor  and  lay  it  on 
the  map,  curved  edge  to  the  north,  with  the  line  run- 
ning between  the  point  in  the  center  of  the  base  line 


MILITARY   SIGNALING.  43 

and  ninety  degrees,  on  a  meridian  line,  and  with  the 
point  in  center  of  the  base  line  exactly  over  where  the 
pencil  line  crosses  the  meridian. 

Note  the  number  of  deg'rees  from  north  at  which 
the  pencil  line  crosses.  If  the  line  crosses  the  circle 
on  that  side  of  north  to  which  the  needle  varies,  sub- 
tract the  variation  from  the  number  of  degrees  from 
north  at  which  the  pencil  line  crosses,  and  if  it  crosses 
to  the  opposite  side  of  north,  add  the  variation  to  the 
number  of  degrees  from  north  at  which  the  line 
crosses,  and  the  result  will  be  the  reading  at  which  the 
compass  needle  should  be  set  in  order  that  the  sight 
line  on  the  cover  shall  be  exactly  in  the  line  between 
the  two  stations. 

A  protractor  should  always  be  carried  in  the  map 
case  with  the  map. 

Road  books,  such  as  are  prepared  in  many  States 
for  the  use  of  cyclists,  should  be  issued  when  practi- 
cable, as  they  contain  information  as  to  grades  and 
condition  of  roads  which  may  often  be  of  much  value. 

MILITARY  PHOTOGRAPHY. 

53.  The  successful  employment  of  photography  in 
military  operations  is  of  recent  date,  and  is  due  to 
modern  improvements  in  apparatus  and  methods 
which  have  rendered  its  operations  practicable  in  the 
I  field. 

U  Photography  is  one  of  the  most  important  aids  for 
tihe  rapid  acquirement  of  military  information.  The 
l^ompactness  of  modern  apparatus  and  the  rapidity  of 
r^)hotographic  processes  render  the  reproduction  of  ter- 
iene  and  enemies'  works  or  positions  the  labor  of  but 
few  hours. 


44  INSTRUCTIONS  IN 

54.  A  military  photograph  possesses  value  from 
the  fact  that  it  contains  an  accurate  and  graphic  de- 
scription of  the  object  desired,  and  can  be  made  in  a 
short  space  of  time. 

Artistic  effect  is  not  essential,  for  the  photograph 
is  desired  as  a  source  of  information,  and  the  prime 
requisite  is  absence  of  failure,  for  re-exposure  will  sel- 
dom be  possible. 

65.  Technical  rather  than  artistic  skill  should  be 
cultivated.  In  reconnoitering  work  the  camera  is  es- 
pecially valuable,  as  the  entire  locality  can  be  photo- 
graphed in  a  few  minutes  and  the  finished  prints  can 
be  ready  by  the  time  the  descriptive  report  is  written, 
thereby  giving  the  commanding  officer  a  full  and  de- 
tailed source  of  information. 

Ordinarily  it  will  not  be  necessary  to  photograph 
much  of  the  landscape,  but  important  places  and  ob- 
jects only,  such  as  bridges,  ravines,  defiles,  forts,  field 
works,  guns,  magazines,  buildings,  ships,  fords,  land- 
ing places,  villages,  signal  stations,  etc. 

56.  Any  magazine  camera  with  a  rapid  rectilineal 
lens,  which  can  be  loaded  in  daylight,  with  films  put 
up  in  cartridge  form  on  rolls  of  a  capacity  of  twelve 
to  one  hundred  exposures,  may  be  used. 

The  essential  requirements  are  lightness,  compact- 
ness, strength,  thoroughly  seasoned  wood,  and  metal 
•parts  strong  and  accurately  made. 

A  camera  which  takes  a  picture  five  by  seven  inches 
is  preferable.  The  bellows  should  be  made  of  red 
Russia  leather,  since  red  ants  will  not  eat  this  kind  of 
leather. 

57.  After  the  exposures  have  been  made  they  may 
be  developed  in  the  field  in  a  dark  room  of  cubical 
form,  five  feet  by  four  feet  by  three  feet  on  the  edges, 


MILITARY  SIGNALING.  45 

made  of  rubber  blankets,  or  of  one  thickness  of  black 
alpaca  and  one  of  turkey-red  cotton  sewed  together, 
one  end  being  doubled  so  as  to  fold  back  like  a  cur- 
tain. 

The  edges  should  be  served  with  rope  and  eyes 
worked  in  the  corners  of  the  top  so  that  it  can  be  sus- 
pended in  a  common  wall  tent.  An  ordinary  camp 
lantern,  with  a  couple  of  thicknesses  of  ruby  cloth  or 
envelope  paper,  will  serve  as  an  illuminant  for  the 
dark  room.  A  couple  of  rubber  trays,  celluloid  solu- 
tion bottles,  graduates,  the  necessary  chemicals  in  cap- 
sule or  tabloid  form,  printing  frame,  and  some  ready- 
sensitized  paper,  will  prove  sufficient  for  all  the  exi- 
gencies of  hasty  field  work. 

68.  Amateur  photography  is  now  so  common  that 
it  will  be  possible  to  find  in  any  signal  corps  men  with 
some  knowledge  of  the  art.  A  few  of  these  should  be 
detailed  for  instruction  and  practice  in  military  pho- 
tography in  order  that  they  may  be  prepared  at  any 
time  to  accompany  reconnoitering  or  inspecting  offi- 
cers. It  has  been  very  recently  proved  that  by  the  use 
of  a  camera  suspended  from  kites  it  is  possible  to  pho- 
tograph an  army  or  columns  of  troops  at  a  distance  of 
five  miles.  For  detailed  instructions,  see  Manual  of 
Photography,  War  Department,  Document  No.  5, 
Office  of  the  Chief  Signal  Officer. 

TRANSPORTATION  OF  APPARATUS.       . 

59.  The  most  economical,  rapid,  and  satisfactory 
method  of  transporting  signalmen  and  signal  appara- 
tus is  by  bicycle. 

The  bicycle  should  have  pneumatic  tires  and  a  dia- 
mond frame,  with  the  largest  possible  space  for  lug- 


46  INSTRUCTIONS  IN 

gage  case ;  should  be  equipped  with  coasting  brackets, 
brake,  and  handle  bars  level  with  the  saddle ;  should 
not  be  of  too  narrow  tread,  and  should  weigh  not  less 
than  twenty-three  nor  more  than  thirty  pounds.  All 
bright  parts  should  be  blued  like  a  rifle  barrel,  to  ren- 
der less  conspicuous  and  to  prevent  rust. 


Signal  corps  equipped  with  bicycles.  ^ 

60.  It  is  a  fundamental  rule  that  the  weight  shall 
be  carried  on  the  wheel  and  not  on  the  man.  The  pis- 
tol and  haversack  only  should  be  carried  on  the  per- 
son, and  it  is  often  advisable  to  attach  the  haversack 
to  the  machine. 

The  signal  apparatus  should  be  distributed  among 
the  men  in  the  party  in  such  proportion  as  to  equalize 
the  load  as  far  as  possible.  A  man  should  not  be  re- 
quired to  carry  both  heliograph  case  and  tripods,  if 
avoidable.  One  man  should  carry  the  case,  and  anoth- 
er the  tripods.  The  heliograph  case  must  always  be 
suspended  over  a  rolled  blanket  in  such  a  way  that 


MILITARY  SIGNALING. 


47 


it  can  not  touch  any  part  of  the  bicycle,  as  the  jar 
might  injure  the  instruments.  A  handkerchief  or  a 
piece  of  cloth  should  be  stuffed  in  the  mirror  box  to 
keep  the  mirrors  from  rattling-. 

61.  To  load  the  bicycle,  tig-htly  roll  a  blanket  in  a 
roll  about  eighteen  inches  long  and  strap  to  front  of 
handle  bar.  Take  mirror-bar  case  off  the  shoulder 
sling  of  heliograph  case  and  lay  it  on  top  of  blanket. 


Military  bicycle,  loaded. 


With  heliograph  case,  tripods,  flag  kit,  blanket,  shelter  tent, 
luu^t^aofe  case,  and  canteen. 


Take  one  turn  of  the  shoulder  sling  around  each  end 
of  mirror-bar  case,  pass  shoulder  sling  under  upper 
tube  of  diamond  frame  near  the  steering  head,  and 
buckle  tightly  enough   so  that  the  case   hangs  sus- 


48  INSTRUCTIONS  IN 

pended  in  front  of  the  blanket  roll,  not  touching  bi- 
cycle. 

Pass  a  strap  around  case  and  steering  head,  to  keep 
case  from  flying  up  and  becoming  displaced.  Strap 
flags  in  flag  case,  made  for  the  purpose,  tightly  to  right- 
hand  side  of  upper  bar  of  frame.  Strap  heliograph 
tripods  in  skeleton  case  tightly  to  frame  on  top  of  flag 
case.  Attach  canteen  under  back  of  saddle,  and  tie  in 
bottom  to  frame  so  as  to  prevent  rattling. 

The  luggage  case,  which  serves  as  a  knapsack, 
should  always  be  kept  in  the  bicycle.  When  shelter 
tents  are  carried,  a  jointed  pole  is  rolled  in  center  of 
the  blanket  roll  and  half  a  tent  rolled  around  blanket. 
Pegs  should  be  packed  in  luggage  case. 

The  torch  kit,  or  oil  canteen,  is  packed  by  suspend- 
ing over  blanket  roll  in  place  of  heliograph  case. 
Hand  axes  are  carried,  with  a  leather  case  protecting 
the  blade,  and  attached  to  bicycle  in  any  convenient 
place.  Field  glasses  and  telescopes  may  be  carried 
either  on  the  person  or  the  machine.  Ponchos  should 
be  rolled  in  a  tight  roll  and  strapped  on  top  of  upper 
bar  of  frame  so  as  to  be  easily  accessible. 

Every  man  should  have  a  cyclometer,  tool  bag, 
and  tire  repair  outfit,  and  every  party  a  camera. 

62.  It  has  been  found  that  the  average  rate  of 
march  of  cyclists  with  full  equipment  is  six  miles  per 
hour.  A  halt  of  ten  minutes  should  be  made  half  an 
hour  after  starting,  and  a  halt  of  ten  minutes  every 
hour  thereafter.  The  men  should  at  the  completion  of 
the  march  be  in  condition  for  signaling  or  for  further 
and  hard  riding  if  necessary. 

63.  Signalmen  should  be  armed  with  the  revolver 
only,  worn  on  a  web  thimble  cartridge  belt,  behind 
the  right  hip. 


MILITARY  SIGNALING.  49 

Campaign  hats  should  be  worn  in  the  field,  a  blue 
or  gray  flannel  shirt,  blouse  with  pockets  in  the  breast 
for  pencils  and  paper,  re-enforced  trousers,  cavalry 
canvas  leggings,  and  stout  shoes. 

The  overcoat  should  not  be  taken  unless  it  be  cold 
enough  to  wear  it.  In  warmer  weather  the  detachable 
cape  may  be  taken  in  its  place. 

ORGANIZATIOIS',  EQUIPMENT,  AND  COMMAND. 

64.  The  chief  signal  officer  of  an  army  in  the  field 
commands  the  signal  corps  serving  therein.  Orders 
affecting  them  will  be  transmitted  through  him,  and  he 
will  be  responsible  that  they  are  fully  instructed,  ade- 
quately supplied,  and  that  they  properly  perform  their 
duties.  He  will  keep  himself  informed  of  the  position 
of  the  army  and  of  the  enemy,  and  under  the  instruc- 
tions of  the  general  commanding  will  establish  his  sta- 
tions to  the  greatest  advantage.     (Army  Regulations.) 

Signal  officers  in  the  field  will  report  to  their  im- 
mediate commanders  and  to  the  chief  signal  officer, 
for  the  information  of  the  general  commanding,  all 
movements  of  the  enemy  and  other  facts  of  interest  to 
the  service  coming  within  their  knowledge.  (Army 
Regulations.) 

65.  A  signal  corps  should  be  attached  to  each  bri- 
gade under  the  command  of  the  brigade  signal  officer, 
who  should  be  a  member  of  the  staff  of  the  brigade 
commander.  The  corps  should  be  composed  of  intel- 
ligent men  enlisted  especially  for  the  service,  and 
shouJd  number  one  officer  and  nine  men  to  each  regi- 
ment in  the  brigade,  with  an  assistant  surgeon,  a  first 
sergeant,  a  quartermaster  sergeant,  and  a  commissary 
sergeant  in  addition. 

4 


50  INSTRUCTIONS  IN  MILITARY  SIGNALING. 

66.  The  unit  of  one  officer  and  nine  men  consti- 
tutes a  ''  section."  Each  section  should  consist  of  one 
first  lieutenant,  one  sergeant,  two  corporals,  and  six 
privates.  A  signal  corps  for  a  brigade  of  four  regi- 
ments would  consist  of  four  first  lieutenants,  one  as- 
sistant surgeon  (first  lieutenant),  one  first  sergeant, 
one  quartermaster  sergea];it,  one  commissary  sergeant, 
four  sergeants,  eight  corporals,  and  twenty-four  privates 
— total,  forty -four — all  under  the  command  of  the  bri- 
gade signal  officer  (of  grade  of  major  or  captain). 

If  the  regiments  composing  the  brigade  are  sta- 
tioned in  different  places,  a  section  of  the  signal  corps 
may  be  located  with  each  regiment. 

Signalmen  should  be  mounted  on  bicycles,  which 
may  be  purchased  or  hired,  as  may  be  most  expedient. 

67.  The  visual  signal  equipment  for  a  corps  of  the 
above  strength  should  consist  of  not  less  than — 

.     8  heliographs. 

32  fiag  kits,  each  containing  two  flags  with  one 
staff. 

8  Graham-Meyer  torch  kits. 

8  telescopes. 

8  field  glasses. 

No  rules  can  be  laid  down  for  electric  equipment. 
When  the  Army  shall  have  adopted  a  standard  appa- 
ratus for  telegraphing  and  telephoning,  instructions 
for  its  use  will  be  prepared. 


APPENDIX  I. 


The  Morse  Telegraph  Code. 


ALPHABET. 

A-—        F K P U 

B O L Q V. 

C  --    -      H M E-    --  W 

jy I   --  N— -         S  ---  X 

E  -  J O  -    -         T  —  Y 

Z---    -        &-    --- 

NUMERALS. 

1 3 5 7 9_ 

2-- 4 6 8 0- 


PUNCTUATION. 

Corama, Exclamation, 

Semicolon,  Si  Parenthesis,  Pn 

Colon,  Ko  Brackets,  Bx 

Period, Dollar  mark,  Sx 

Interrogation, Dash,  Dx 

Quotation,  Qn  Hyphen,  Hx 

Paragraph, Underline,  Ux 

51 


52  APPENDIX  I. 


SIGNALS. 

1.  Wait  a  moment. 

4.  Start  me. 

5.  Have  you  anything  for  me  ? 

7.  Are  you  ready  ? 

8.  Busy  on  other  wires  (or  stations). 

9.  Train  order  (or  important  military  message)— 

give  way. 
13.  Do  you  understand  ? 
18.  What  is  the  matter  ? 
27.  Adjust  your  magnet. 
30.  Circuit  closed  (or  close  station). 
44.  Answer  quick. 
73.  Accept  compliments. 
92.  Deliver  (ed). 
134.  Who  is  at  the  key  ? 

ABBREVIATIONS. 

Ahr-^Another.  G  R — Government  rate. 

Ans — Answer.  N  M — No  more. 

Ck — Check.  O  B — Official  business. 

Col— Collect.  O  K— All  right. 

D  H — Dead  head.  Opr — Operator. 

G  A— Go  ahead.  Pd— Paid. 

G  E~Good  evening.  Qk — Quick. 

G  M — Good  morning.  Sig — Signature. 

G  N— Good  night. 


APPENDIX   11. 


The  Myer  code  may  be  used  for  telegraphing"  by 
men  not  familiar  with  the  Morse  telegraph  code.  One 
tick  is  made  for  "1,"  two  ticks  in  quick  succession 
for  "2,"  and  three  ticks  in  quick  succession  for  "3." 
Pauses  between  the  elements  of  a  letter  should  be  dis- 
tinct, but  not  too  long. 

Dwell  slightly  upon  the  pause  between  letters. 


A. 
B. 
C. 
D. 
E. 
F. 
G. 
H. 
L. 
J. 
K. 
L. 
M. 
N. 
O. 


THE  MYER  CODE   FOR  TELEGRAPHING. 

22 

2112 

121 

222 

12 


.2221 
.2211 
..122 
....1 
.1122 
.2121 
.221 
.1221 
...11 
...21 


53 


APPENDIX  II. 
P... 1212 

Q 1211 

E 211 

S 212 

T 2 

U 112 

V 1222 

W ..1121 

X 2122 

Y Ill 

Z 2222 

NUMERALS. 

1 nil 

2 2222 

3 1112 

4 2221 

5 1122 

6 2211 

7 1222 

8 2111 

9 1221 

0 2112 


APPENDIX  III. 


Table  of  the  Magnetic  BecUnatioyi  at  Various  Points 
in  the  United  States— for  the  Epoch  1900, 

The  magnetic  declination  (or  variation  of  the  com- 
pass, as  it  was  formerly  called  by  surveyors  and  still  is 
by  navigators)  at  any  place,  is  the  angle  contained  be- 
tween two  vertical  planes,  one  being  the  astronomical 
or  true  meridian,  and  the  other  the  plane  in  which 
the  horizontal  axis  of  a  freely  suspended  magnet  lies 
at  the  time. 

The  declination  is  called  ''West"  when  the  north 
end  of  a  magnet  points  to  the  west  of  true  north,  and 
"  East "  when  the  north  end  of  the  magnet  points  to 
the  east  of  true  north. 

The  agonic  line  or  zero  curve  of  the  Western  Hemi- 
sphere, a  line  at  all  points  upon  which  the  magnet 
points  to  the  true  north,  crosses  the  United  States 
(1890)  ,\n.  a  generally  southerly  direction ;  entering 
at  the  junction  of  Lake  Michigan  and  Lake  Huron, 
passing  through  the  center  of  the  State  of  Michigan, 
touching  the  western  extremity  of  Lake  Erie,  souther- 
ly through  the  State  of  Ohio,  and  following  the  gen- 
eral direction  of  the  boundary  line  between  Kentucky 
and  West  Virginia,  it  curves  slightly  to  the  eastward, 
55 


56  APPENDIX  III. 

and  then,  following  the  direction  of  the  Great  Pedee 
River,  passes  just  to  the  eastward  of  Charleston,  S.  C. 

At  points  east  of  the  agonic  line  the  declination  is 
west.  At  points  west  of  the  agonic  line  the  .declina- 
tion is  east. 

At  present  there  is  generally  throughout  the  United 
States  an  annual  westward  increase  of  declination, 
varying  from  0'  to  5',  which  has  been  considered  in 
computing  the  declination  as  of  the  year  1900. 

The  declinations  given  are  to  the  nearest  degree, 
which  is  sufficiently  precise  for  ordinary  use  by  the 
Signal  Corps. 

The  values  given  may  be  used  without  sensible  in- 
accuracy for  four  or  five  years  before  and  after  1900. 

LOCALITY.  DECLINATION. 

Alabama,  Central  part 3°  E. 

Western  part 4°  E. 

Arkansas,  Eastern  part 5°  E. 

Central  part. 6°  E. 

Western  part 7°  E. 

Arizona,  Southeastern  part 13°  E. 

Central  part 14°  E. 

Northwestern  part 15°  E. 

California,  Los  Angeles 14°  E. 

Tulare  Lake 15°  E. 

Santa  Cruz 16°  E. 

Sacramento 17°  E. 

Northwestern  part 18°  E. 

Colorado,  Southeastern  part 13°  E. 

Central  part 14°  E. 

Northwestern  part 15°  E. 

Connecticut,  New  London 11°  W. 

Stamford 10°  W. 


APPENDIX  III.  57 

LOCALITY.  DECLINATION. 

Delaware 6°  W. 

District  of  Columbia 5°  W. 

Florida,  Eastern  coast 1°  E. 

Western  coast 2**  E. 

Pensacola 4°  E. 

Georgia,  Eastern  part 1°  E. 

Central  and  western  parts 2°  E. 

Idaho,  Southeastern  part 18°  E. 

Central  part 19°  E. 

Bald  Mountain 20°  E. 

Extreme  northwest 22°  E. 

Illinois,  Eastern  part 3°  E. 

Central  part 4°  E. 

Western  part 5°  E. 

Indian  Territory 9°  E. 

Indiana,  Eastern  part 1°  E. 

Central  part 2°  E. 

Western  part 3°  E. 

Iowa,  Eastern  part 6°  E. 

Des  Moines 7°  E. 

Audubon 8°  E. 

Western  part 9°  E. 

Kansas,  Kansas  City 8°  E. 

Manhattan 9°  E. 

Larned 10°  E. 

Western  part 11°  E. 

Kentucky,  Eastern  extremity No  variation. 

Central  part 2°  E. 

Western  part 4°  E. 

Louisiana,  Eastern  part 5°  E. 

Western  part 6°  E.    • 

Maine,  Saco 14°  W. 

Portland 15°  W. 

5 


58  APPENDIX  III. 

LOCALITY.  DECLINATION. 

Bangor 17°  W. 

Northern  part 20°  W. 

Maryland,  Baltimore 5°  W. 

Cumberland 4°  W. 

Massachusetts,  Gloucester 13"*  W. 

Boston 12°  W. 

Central  part 11°  W. 

Michigan,  Detroit 2°  W. 

Central  part No  variation. 

Western  part 1°  E. 

Minnesota,  Eastern  part. 8°  E. 

Western  part 9°  E. 

Mississippi,  Eastern  part  •.  4°  E. 

Western  part ...".. 5°  E. 

Missouri,  St.  Louis 5°  E. 

Eolla 6°  E. 

Sedalia 7°  E. 

Montana,  Southeastern  part 17°  E. 

Yellowstone  County 18°  E. 

Virginia  City 19°  E. 

Missoula 20°  E. 

Nebraska,  Lincoln 10°  E. 

Grand  Island 11°  E. 

Ogallala 12°  E. 

Nevada,  Southern  part 16°  E. 

Central  part 17°  E. 

Northern  part 18°  E. 

New  Hampshire,  Manchester 13°  W. 

Lake  Winnepesaukee 14°  W. 

Northern  part 16°  W. 

New  Jersey,  Southern  part 7°  W. 

Central  part 8°  W. 

Northern  part 9°  W; 


APPENDIX  III.  59 

LOCALITY.  DECLINATION. 

New  Mexico,  Southeastern  part 12°  E. 

Central  part 13°  E. 

Northwestern  part 14°  E. 

New  York,  BuJffalo 6°  W. 

Rochester 8°  W. 

Oswego 9°  W. 

New  York  city 9°  W. 

Utica 10°  W. 

Albany 11°  W. 

Adirondacks 12°  W. 

Plattsburg 14°  W. 

North  Carolina,  Cape  Hatteras 5°  W. 

New  Berne 3°  W. 

Raleigh 2°  W. 

Great  Pedee  River No  variation. 

Asheville 1°  E. 

North  Dakota,  Eastern  part 12°  E. 

Central  part 15°  E. 

Western  part 17°  E. 

Ohio,  Eastern  part 2°  W. 

Central  part No  variation. 

Western  part 1°  E. 

Oklahoma 10°  E. 

Oregon,  Southern  part 18°  E. 

Central  part 19°  E. 

Northern  part 20°  E. 

Pennsylvania,  Wilkesbarre 8°  W. 

Williamsport 7°  W. 

Philadelphia 6°  W. 

Johnstown 5°  W. 

Pittsburg 4°  W. 

Rhode  Island 12°  W. 

South  Carolina,  Eastern  part No  variation. 


60  APPENDIX  III. 

LOCALITY.  DECLINATION. 

Central  part 1°  E. 

Western  part 2°  E. 

South  Dakota,  Eastern  part 11°  E. 

Central  part 12°  E. 

Western  part 14°  E. 

Tennessee,  Eastern  extremity. .....  No  variation. 

Central  part 2°  E. 

Western  part 4°  E. 

Texas,  Corpus  Cliristi 8°  E. 

Dallas 9°  E. 

Sherwood 10^  E. 

Midland 11°  E. 

Utah,  Southern  part 15°  E. 

Central  part 16°  E. 

Black  Mountains 18°  E. 

Salt  Lake 16°  E. 

Vermont,  Southern  part 13°  W. 

Central  part 14°  W. 

Northern  part 15°  W. 

Virg-inia,  Richmond , . . .     4°  W. 

Liberty .^°  W. 

Marion No  variation. 

Washington  (State),  Southern  part 21°  E. 

Central  part 22°  E. 

Northern  part. 23°  E. 

West  Virginia,  Eastern  part 3°  W. 

Central  part 2°  W. 

Western  extremity No  variation. 

Wisconsin,  Milwaukee. 3°  E. 

Fond  du  Lac 4°  E. 

Eau  Claire 6°  E. 

Wyoming,  Fort  Laramie 15°  E. 

Sweet  Water  Mountains 16°  E. 


APPENDIX  III.  61 

LOCALITY.  DECLINATION. 

Shoshone  Reservation 17°  E. 

Yellowstone  National  Park 18°  E. 

For  maps  and  complete  data  as  to  magnetic  decli- 
nation in  the  United  States,  see  Appendix  No.  7,  1888, 
and  Appendix  No.  11, 1889,  to  the  Reports  of  the  United 
States  Geodetic  and  Coast  Survey. 


INDEX. 


References  are  to  Paragraphs, 


Abbreviations.  1. 

Adjustment  of  Heliograph,  19,  20, 

21,  25,  26. 
Agonic  Line,  Appendix  III. 
Alignment  of  Heliograph,  19,  20, 

21,  25,  26. 
Alphabet,  1. 
Apparatus,  Transportation  of,  59- 

63. 
Axe,  where  carried,  61. 

Backgrounds,  40,  41,  42. 

Bicycles,  59-63,  66. 

Blanket  under  Heliograph,  60,  61. 

Camera,  56, 
Canteen,  61. 
Cipher  Disk,  45. 
Cipher  Messages,  45.  46,  47. 
Circle  of  Illumination.  30. 
Codes,  1,  Appendices  I  and  II. 
Code  Calls,  3. 
Compass,  49,  50. 

Compass,  Variation  of,  49,  52,  Ap- 
pendix III. 
Conventional  Signals,  2. 
Cyclometer,  61. 

Deciphering  Messages,  47.' 
Declination,  Magnetic,  Appendix 

Description,  of  Bicycle,  59. 
of  Camera,  56. 


63 


Description,  of  Compass,  50. 

of  Dark  Room,  57. 

of  Field  Map,  51. 

of  Flag,  10. 

of  Heliograph.  14. 

of  Loaded  Bicycle,  61. 

of  Torch,  12. 

of  Uniform,  63. 
Disks,  Cipher,  45. 
Distances,  Flag,  11. 

Heliograph,  31. 
Duties,  Men  on  Stations,  33-36. 

Enciphering  Messages,  46. 
Equipment,  Visual  Signal,  67. 

Field  Stations,  32-44. 

Duties  of  Chief  of,  34,  35. 
Field  Books,  39. 
Fires,  42. 
Flag,  The,  10. 
Flash    Signals,  with    Heliograph 

Search  Light  or  Lantern,  7, 

22. 
Flying  Torch,  The,  12,  13,  42. 
Foot  Torch,  The,  12,  13,  42. 
Front  Motion,  5,  11,  42. 

Haversack.  60. 
Heliograph,  14. 

Adjustment  of,  19,  20,  21,  25,  26. 

Alignment  of,  19,  20.  21,  25,  26. 

Transportation  of,  59-61. 


64 


INDEX. 


Information,  to  be  reported,  64. 
Instructions  for  using  Myer  Sys- 
tem, 4. 
Invisible  Ink,  48. 

Lanterns,  Signaling  with,  5. 
Line  of  Visiofi,  11,  13,  42,  43. 
Luggage  Case,  59. 

Magnetic  Declination,  49,  52,  Ap; 
pendix  III. 

Courses,  to  find,  49,  52. 
Maps,  39,  51,  52. 
Matches,  13. 
Messages,  Order  of,  9. 

by  Messengers,  48. 
Military  Photography,  53-58. 
Morse  Code,  Appendix  I. 
Myer  Code  for  Telegraphing,  Ap- 
pendix II. 
Myei»  System  of  Signaling,  1-8. 

Night  Signaling,  37,  42,  43. 
Numerals,  1. 

Order  of  Message,  9. 
Organization,  04-66. 

Position  of  Men  in  Signaling,  33, 

of  Stations,  37,  38. 
Precision,  36. 

Pronouncing  Myer  Alphabet,  9. 
Photography,  Military,  53-58. 

Recording  Signals,  33. 
Recruits,  Instruction  of,  11. 


Rhythm  of  Heliograph,  22. 
Road  Book,  52. 

Scoop,  against  Wind,  11. 

Signal  Codes,  1,  Appendices  I  and 

II. 
Signal  Corps,  Organization  of,  65, 

66. 
Signaling,   with  Flag,   Torch,  or 

Hand  Lantern,  5,  33,  40,  41, 

42,  43. 
with  Heliograph,  22,  44. 
Size  of  Flags,  10. 
Sound  Signals  with  Fog  Whistle, 

Fog  Horn,  or  Bugle,  8. 
Speed,  36. 
Staff,  10. 
Stakes,  11. 
Stations,    where    to    be   located, 

37. 
where  not  to  be  located,  37. 

Table   of   Magnetic   Declination, 

Appendix  III. 
Torch,  Description  of,  12. 

Signaling  with,  13. 
Transportation  of  Apparatus,  59- 


Variation  of  the  Compass,  49,  52, 

Appendix  III. 
Vertical  Motions,  5. 
Vision,  Line  of,  11,  13,  42,  43. 

Zero  Circle,  Appendix  III. 


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